Suppose X is a random variable with mean μ and standard deviation σ. If a large number of trials is observed, at least what percentage of these values is expected to lie between μ − 2σ and μ + 2σ? (Round your answer to the nearest whole number.)

At least ____%

I got 95.. am I doing this correctly?

Question

Suppose X is a random variable with mean μ and standard deviation σ. If a large number of trials is observed, at least what percentage of these values is expected to lie between μ − 2σ and μ + 2σ? (Round your answer to the nearest whole number.)

At least ____%

I got 95.. am I doing this correctly?

anonymous · Answer

Yes, although "at least" should be "approximately"

anonymous · Answer

When I submit the answer it says it's incorrect :(

anonymous · Answer

The tails have 2.27% x 2 = 4.54% of the values beyond +- 2 standard deviations, so a bit more than 95% is expected within these limits. 95% should be correct.

anonymous · Answer

Thanks!

anonymous · Answer

You are quite welcome.